 /*******************************************************************************
  * Copyright (c) 2000, 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.core.internal.runtime;

 import java.io.IOException ;
 import java.net.URL ;
 import org.eclipse.core.internal.boot.PlatformURLConnection;
 import org.eclipse.core.internal.boot.PlatformURLHandler;
 import org.eclipse.osgi.util.NLS;
 import org.osgi.framework.Bundle;

 /**
  * Platform URL support
  * platform:/fragment/fragmentId/ maps to fragmentDescriptor.getInstallURLInternal()
  */
 public class PlatformURLFragmentConnection extends PlatformURLConnection {

     private Bundle target = null;
     private static boolean isRegistered = false;
     public static final String FRAGMENT = "fragment"; //$NON-NLS-1$

     /*
      * Constructor for the class.
      */
     public PlatformURLFragmentConnection(URL url) {
         super(url);
     }

     /* (non-Javadoc)
      * @see org.eclipse.equinox.internal.url.PlatformURLConnection#allowCaching()
      */
     protected boolean allowCaching() {
         return true;
     }

     /* (non-Javadoc)
      * @see org.eclipse.equinox.internal.url.PlatformURLConnection#resolve()
      */
     protected URL resolve() throws IOException {
         String spec = url.getFile().trim();
         if (spec.startsWith("/")) //$NON-NLS-1$
 spec = spec.substring(1);
         if (!spec.startsWith(FRAGMENT))
             throw new IOException (NLS.bind(CommonMessages.url_badVariant, url));
         int ix = spec.indexOf("/", FRAGMENT.length() + 1); //$NON-NLS-1$
 String ref = ix == -1 ? spec.substring(FRAGMENT.length() + 1) : spec.substring(FRAGMENT.length() + 1, ix);
         String id = getId(ref);
         Activator activator = Activator.getDefault();
         if (activator == null)
             throw new IOException (CommonMessages.activator_not_available);
         target = activator.getBundle(id);
         if (target == null)
             throw new IOException (NLS.bind(CommonMessages.url_resolveFragment, url));
         URL result = target.getEntry("/"); //$NON-NLS-1$
 if (ix == -1 || (ix + 1) >= spec.length())
             return result;
         return new URL (result, spec.substring(ix + 1));
     }

     public static void startup() {
         // register connection type for platform:/fragment handling
 if (isRegistered)
             return;
         PlatformURLHandler.register(FRAGMENT, PlatformURLFragmentConnection.class);
         isRegistered = true;
     }
 }

